Various Visual Issues

I will try to avoid making this an infodump and get straight to the issue.
I’ve got ugly “screen door” effects all over the ground and weird ghostly outlines around enemies + objects on Halo Reach. This is probably present on the other games too but I’ve explicitly noticed the most on Reach. Any advice or recommendations are greatly appreciated other than “submit a support ticket”, as I’ve already been down that road for other problems and it’s an absolute dead end.

Visual Issues:
https://dl.dropboxusercontent.com/s/0an58xzc50d89xt/Visuals.jpg?dl=0
(various obvious spots are marked with arrows)

This seems to be the ONLY thing that fixes it-- setting graphics to performance:
https://dl.dropboxusercontent.com/s/iymg1p1nqm93ro7/fix.jpg?dl=0
(as you imagine, things look pretty ugly in a different way)

Original, enhanced, and even custom presets [with a potentially problematic setting turned off] does NOT solve the issue:
https://dl.dropboxusercontent.com/s/4lahi5tx75fkzad/nofix.jpg?dl=0

Have you tried verifying file integrity?

Have you overclocked anything on your PC at all? Overclocks can sometimes do weird things in games.